Method for modifying aroma-containing gas

Abstract

A method for modifying an aroma-containing gas comprising volatile components recovered from coffee, characterized by contacting the aroma-containing gas with molecule sieve carbon oxidized with a strong acid is disclosed. This method removes undesirable components from the coffee aroma-containing gas by adsorption.

I claim: 
     
       1. A method for modifying an aroma-containing gas comprising volatile components recovered from a food material, said method comprising contacting said aroma-containing gas with molecular sieve carbon oxidized with a strong acid. 
     
     
       2. The method of claim 1, wherein said food material is coffee. 
     
     
       3. The method of claim 1, wherein said aroma-containing gas is selected from the group consisting of a gas generated during the roasting of coffee beans, a gas generated during the grinding of roasted coffee beans, and a gas generated during the supply of water or a coffee extract or steam to ground roasted coffee and combinations thereof. 
     
     
       4. The method of claim 1, wherein said molecular sieve carbon oxidized with said strong acid is molecular sieve carbon in which the pores having pore diameters of 0.4 to 0.8 nm account for 70% or more of the total volume, and which has a total pore volume of 0.15 to 0.7 ml/g. 
     
     
       5. The method of claim 1, wherein molecular sieve carbon has surface oxygen functional groups in a total amount of 0.5 mol/kg or more on the carbon surface, and the proportion of the surface oxygen functional groups detected as phenolic hydroxyl groups is 60 mol % or more. 
     
     
       6. The method of claim 1, wherein the oxidation of molecular sieve carbon is performed by immersing molecular sieve carbon in an aqueous solution of a strong acid selected from the group consisting of an aqueous solution of nitric acid with a concentration of at least 1N, an aqueous solution of sulfuric acid with a concentration of at least 1N, and any mixture of these acids.